000 AXPZ20 KNHC 032121 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2121 UTC Mon Jul 3 2017 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURE... A tropical wave is analyzed from 06N108W to 16N108W with a 1010 mb surface low located along the wave near 12N108W. This disturbance has been moving W at around 10 kt during the past 24 hours. Showers and thunderstorms associated with the disturbance have increased in coverage since yesterday, but the circulation remains elongated. Additional development of this system is possible and there is a medium chance a tropical depression could form during the next 48 hours while it moves west- northwestward. Moderate to fresh winds are observed in the E quadrant of the low with combined seas of 6 to 8 ft. ...TROPICAL WAVES... A tropical wave is analyzed from 08N97W to 16N96W. The wave has been moving W at 10 to 15 kt during the past 24 hours. Scattered moderate and isolated strong convection is observed from 08N to 11N between 94W and 100W. A tropical wave is analyzed from 07N110W to 1010 mb low pressure near 13N110W to 17N110W. Scattered moderate to isolated strong convection is noted within 120 nm NW semicircle of the low pressure. This low pressure has been given a medium chance of development during the next 48 hours. See the Special Features section for more details on this system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from eastern Panama near 07N78W to 1010 mb low pressure near 09N86W to 09N97W, then is discontinuous, resuming near 1010 mb low pressure at 13N110W and continuing to another 1010 mb low pressure near 11N120W, then on to 09N125W. The intertropical convergence zone reaches from 09N125W to 08N135W. Scattered moderate convection is observed within 120 nm south of the monsoon trough between 85W and 95W. Scattered moderate convection is also observed within 180 nm either side of monsoon trough and ITCZ between 125W and 130W, and west of 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... For the Gulf of Tehuantepec, the combination local overnight drainage effects along the a tight pressure gradient between ridging to the north and lower pressure to the south will continue to support pulses of fresh to strong northerly gap winds through the Gulf of Tehuantepec with seas reaching as high 9 ft at times each night through the week. Farther north, weak ridging across the region will maintain gentle to moderate northerly breezes through Thu off the coast of the Baja California peninsula, with 3 to 5 ft seas. The winds will increase off Baja California Norte Fri and Fri night as the ridge builds, with moderate to fresh northwest to north winds and 5 to 7 ft seas, lingering through Sat as swell. Looking ahead, seas may build to 7 ft by Sat south of the Revillagigedo Islands by late Sat due a possible tropical cyclone passing well to the south of the islands. Light to gentle breezes and slight seas will persist over the Gulf of California and elsewhere off Mexico through the next several days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... For the Gulf of Papagayo, fresh northeast to east gap flow will pulse each night this week with seas building to 6 ft during the strongest winds. Elsewhere gentle to moderate south to southwest winds are forecast elsewhere early this week. Long period southwest swell in the form of 7 to 9 ft seas, will reach the equator on Wed night and affect the waters west of Colombia and Ecuador, and then begin to subside on Fri. The combination of moist southerly flow near the monsoon trough along with passing tropical waves will maintain weak surface lows and scattered showers and thunderstorms over much of the region north of 04N through the week. REMAINDER OF THE AREA... Moderate to fresh trades between the ITCZ and the subtropical ridge north of the region will diminish through late Tue as the ridge weakens. Seas are 6 to 8 ft north of 20N west of 130W in mixed southeast and northeast swell. Meanwhile, the 1010 mb low pressure near 12N108W will continue to move westward, possibly developing into a tropical cyclone over the next couple of days as it crosses 120W. Even if this low pressure does not form into a tropical cyclone, expect fresh to strong winds, seas to 8 ft, and scattered showers and thunderstorms from 10N and 15N between 115W and 130W by mid week. Looking ahead, while most global models show the low currently near 12N108W weakening late in the week as it shift westward, they also show good agreement that a second low pressure will form farther to the east, then move to the south of Clarion Island by late Sat. Please refer to the NHC Tropical Weather Outlook for the East Pacific at hurricanes.gov for more information. $$ Christensen